WO2014008990A1

WO2014008990A1 - Method for operating a heat exchanger and hvac installation for implementing the method

Info

Publication number: WO2014008990A1
Application number: PCT/EP2013/001934
Authority: WO
Inventors: Markus Friedl; Marc Thuillard
Original assignee: Belimo Holding Ag
Priority date: 2012-07-09
Filing date: 2013-07-02
Publication date: 2014-01-16
Also published as: US9982955B2; EP2870414A1; US20150153119A1; RU2015104061A; EP2870414B1; RU2632070C2; CN104641184A; US20180238645A1; US10132576B2; CH706736A1; CN104641184B

Abstract

The invention relates to a method for operating a heat exchanger (15). On a primary side, a heat transfer medium flows through the heat exchanger (15), which heat transfer medium enters the heat exchanger (15) with a first temperature (T^W _ein) and exits the heat exchanger (15) with a second temperature (T^W _aus). On a secondary side, the heat exchanger emits a heat flow (Q) to a secondary medium flowing through the heat exchanger (15) in the case of heating or in the case of cooling absorbs a heat flow (Q) from the secondary medium, which enters the heat exchanger (15) with a third temperature (T^L _ein) and exits the heat exchanger (15) again with a fourth temperature (T^L _aus), wherein the heat exchanger (15) is capable of transferring a maximum heat flow. A simplified control system is characterized in that at least three of the four temperatures (T^W _ein, T^W _aus, T^L _ein, T^L _aus) are measured, and the degree of saturation of the heat exchanger (15) at any time is determined from these measured temperatures, which degree of saturation is used to control the operation of the heat exchanger (15).

Description

Proceeding with the operation of a heat exchanger and HVAC plant for the execution of the proceedings

TECHNICAL FIELD The present invention relates to the field of air conditioning technology. It relates to a method for operating a heat exchanger according to the preamble of claim 1. It also relates to an HVAC plant for carrying out the process.

STATE OF THE ART

For the heating, cooling, air conditioning and ventilation of premises in buildings usually central facilities are used, which are summarized under the term HVAC systems. HVAC stands for Heating, Ventilation and Air Condi- tioning. In such HVAC systems, heat and / or cold are generated centrally and conducted via a suitable heat transfer medium, usually water, to the appropriate premises, where the heat or cold is released via local heat exchangers, for example to the local air.

The heat flow required to reach a given room temperature and emitted or absorbed via the local heat exchanger is frequently regulated by the fact that the primary-side mass flow of the heat transfer medium is changed accordingly. A section of an exemplary HVAC system is shown in FIG. 1. The HVAC system 1 0 'of Fig. 1 comprises a local heat exchanger 1 5, which is connected on the primary side via a flow branch line 1 3 to a parent flow line 1 1 and a return branch line 1 4 to a parent return line 1 2. Supply line 1 1 and return line 1 2 are connected with a not shown

CONFIRMATION COPY th central means for heat and / or refrigeration connected. On the secondary side of the heat exchanger 1 5 is traversed by an air stream 1 6, which absorbs heat in the heating case and emits heat to the cooling case. For adjusting the mass flow of the heat transfer medium through the primary side of the heat exchanger 1 5 1 control valve 1 7 is arranged in the flow in the branch line 1 3 in the example of Fig., That is controlled by a controller 21.

The output in the heat exchanger 1 5 to the air stream 1 6 heat flow determined from the primary side mass flow of the heat transfer medium, the inlet temperature T _n at the entrance of the heat exchanger 1 5 and its outlet temperature T ^ _s at the output of the heat exchanger 1 5 after the simple relationship Q = rh - c _p - (T _n - T ^ _s ) with the mass flow m and the specific heat c _{p of} the heat transfer medium.

The mass flow is determined by the corresponding volume flow V, which is measured with a flow meter 1 8 used, for example, in the return branch line 1 4. The measurement of the two temperatures T _n and T ^ _s takes place by means of two temperature sensors 1 9 and 20, which are expediently arranged on the primary-side inlet or outlet of the heat exchanger 1 5.

A comparable arrangement is known for example from the document EP 0 035 085 A1, where it is used in connection with a consumption measurement. In addition, a temperature sensor is provided in the room to be heated / conditioned, which controls the supply of the heat transfer medium on the primary side of the heat exchanger. Signaled in this known arrangement now the room temperature sensor (RTS in Fig. 1), an increased heat demand, the valve on the primary side of the heat exchanger is further opened (at constant flow temperature) to provide more heat. The problem here is now that the transmitted via the heat exchanger heat flow Q as a function of the primary-side flow V shows a course that is shown in Fig. 2. The curve depends - as will be explained below - on the one hand on the design of the heat exchanger (in particular from the heat exchanger surface A, the heat transfer coefficient k, a factor F and an exponent n) and on the other hand by the temperature, the mass flow and the heat capacity of Medium on the secondary side of the heat exchanger.

The curve, which initially rises sharply at low volume flows, flattens out more and more as the volume flow increases, approaching asymptotically a limit Q _mx (saturation). The flattening of the curve means that for equal increases in heat flow ever greater increases in volume flow and thus more and more pumping power must be made available. In particular, the power to be expended for the pump increases with the third power of the volumetric flow while the transferred heat increases only slightly. However, this makes little sense from an economic point of view.

It is therefore desirable to limit the volume flow within such a control, when a predetermined value in the ratio -ß-, the degree of saturation of

Heat exchanger is achieved. Such a value can be selected, for example, at 0.8, as shown in Fig. 2. By introducing such a limit value, the pumping power to be applied by the system can be limited, without having to accept large losses of the transferred heat quantity, which leads to advantages in the design and operation of the system. On the other hand, it is also conceivable to change the air flow on the secondary side of the heat exchanger. As already mentioned above, the current heat flow in the heat exchanger and thus the point on the curve shown in FIG. 2 can be determined by measuring the volume flow and the primary-side temperatures. The curve and its asymptote can be determined by controller 21 for certain conditions on the secondary side of the heat exchanger only by measurements over an extended period of time. For this purpose, however, a flow meter is needed, which is relatively expensive and - if it contains moving parts - may also be susceptible to interference.

It would be advantageous for these reasons to have a method by which the degree of saturation of the heat exchanger in operation could be determined and monitored in a simplified manner.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a method for operating a heat exchanger of the type mentioned in such a way that can be dispensed with the use of a flow meter.

It is a further object of the invention to provide an HVAC system for carrying out the method.

These and other objects are achieved by the features of claims 1 and 1 2.

The invention is based on a method for operating a heat exchanger, which heat exchanger flows through a heat transfer medium on a primary side, which enters the heat exchanger at a first temperature and exits the heat exchanger at a second temperature, and on a secondary side in the heating system. case emits a heat flow to a flowing through the heat exchanger secondary medium or in the cooling case receives a heat flow from the secondary medium, which enters the heat exchanger at a third temperature and exits at a fourth temperature from the heat exchanger, the heat exchanger can transmit a maximum heat flow ,

It is characterized in that at least three of the four temperatures are measured, and that from these measured temperatures, the respective degree of saturation of the heat exchanger is determined and used to control the operation of the heat exchanger. An embodiment of the inventive method is characterized in that the flow of heat transfer medium on the primary side of the heat exchanger is steu ^¬ erbar, and that the flow of heat transfer medium is limited to the primary side of the heat exchanger when the degree of saturation of the heat exchanger reaches a predetermined value. Another embodiment of the inventive method is characterized in that the flow of the secondary medium on the secondary side of the heat exchanger is controllable, and that the degree of saturation of the heat exchanger is used to control the flow of the secondary medium.

Basically, on both sides of the heat exchanger (primary side and secondary side), depending on the application and need, a wide variety of media such. Water, air, brine, ice slurry or similar media are used.

In particular, however, the heat transfer medium may be water. In particular, however, the secondary medium may be air.

Another embodiment of the inventive method is characterized in that the heat exchanger is part of a HVAC system.

According to a further embodiment of the invention, the first, second and third or fourth temperature are measured, and for determining the degree of saturation of the heat exchanger, a function of the type - = f (T \, T2, T3) or - = f (T _e Z , T _ae l used.

In principle, the heat exchanger can be operated in the context of the invention in the DC, cross-flow or countercurrent or mixed forms of these types.

In particular, however, the heat exchanger is operated in countercurrent, and is the function for determining the degree of saturation of the heat exchanger

Ö 1 Π - Γ2 Ö 1 T ^w - T ^w

= ₁ or ^ - = lE SBL used.

Q 2 Π - Γ 3 Q 2 T ^w - T

But it is also conceivable that the heat exchanger is operated in countercurrent, and that for determining the degree of saturation of the heat exchanger, the function

- 72

or Q = 1 - a from ö _max 2 · (Θ + «· (1 - Θ)) Π - Γ3 Ö _max 2 · (Θ +« · (1 - Θ)) Τ ^ - Τ ^ is used, where n denotes a power deviating from the value 1 and Θ is a constant which in particular has the value 0.7.

If the secondary medium is air, in the cooling case, in addition, the moisture content of the air can be measured when entering the heat exchanger, which from the Temperatures certain degree of saturation of the heat exchanger to account for taking place in the heat exchanger condensation is corrected accordingly.

Another embodiment of the method according to the invention is characterized in that the flow temperature of the heat transfer medium is increased when the degree of saturation of the heat exchanger reaches a predetermined value.

The HVAC system according to the invention for carrying out the method according to the invention comprises a heat exchanger which is connected on the primary side to a supply line and a return line of a working with a heat transfer medium central heating / cooling system and the secondary side is flowed through by a secondary medium, further comprising a control means for Control of the primary-side mass flow of the heat transfer medium and / or the secondary flow, and a first temperature sensor for measuring the inlet temperature of the entering into the heat exchanger heat transfer medium, a second temperature sensor for measuring the outlet temperature of exiting the heat exchanger heat transfer medium, and a control, which on the input side the first and second temperature sensors are connected, and the output side verbun ^¬ with the control means ^¬ is the.

It is characterized in that at least one third temperature sensor for measuring the inlet temperature and / or outlet temperature of the secondary medium entering the heat exchanger is provided, that the third temperature sensor is connected to an input of the controller, and that the controller is designed so that they controls the control means in accordance with the temperature values measured by the at least three temperature sensors. An embodiment of the HVAC system according to the invention is characterized in that a consumer is connected to the secondary side of the heat exchanger, and that the controller receives demand signals from the consumer via a demand signal line.

Another embodiment of the inventive HVAC system is characterized in that the heat transfer medium is water and the secondary medium is air.

Another embodiment is characterized in that the control means is a control valve which is installed in a leading to the primary side of the heat exchanger flow branch line or return branch line.

A further embodiment is characterized in that the control means is a fan which is installed in an air channel leading to the secondary side of the heat exchanger.

In particular, a humidity sensor for measuring the moisture content of the air flowing into the heat exchanger air is provided, wherein the humidity sensor is connected to an input of the controller.

A further embodiment of the HVAC system according to the invention is characterized in that a flow meter is provided which is installed in a leading to the primary side of the heat exchanger flow branch line or return branch line, and that the flowmeter is connected to an input of the controller.

Yet another embodiment of the HVAC system according to the invention is characterized in that several heat exchangers are arranged in several consumer circuits. net are that the consumer circuits are powered by the central heating / cooling system or power generator via a distributor, that the controller includes a demand control, and that the controller is connected via control lines to the power generator and the distributor. BRIEF EXPLANATION OF THE FIGURES

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it:

Fig. 1 shows a detail of a known HVAC system with a heat exchanger and conventional devices for determining the delivered

Heat flow;

Fig. 2 shows an exemplary dependence of the transmitted from a heat exchanger

Heat flow from the primary-side volume flow (this dependence depends on the heat exchanger operating point for each heat exchanger, in particular on the temperatures and the heat capacity flow (mass flow heat capacity) on the secondary side);

FIG. 3 is a view similar to FIG. 1 of an HVAC system according to an embodiment of the invention; FIG. in a representation comparable to Figure 2, the correction in the determination of the heat flow when cooled with the heat exchanger on the secondary side moist air; 5 shows a basic representation of a countercurrently operated heat exchanger with the characteristic variables or parameters;

FIG. 6 is a view similar to FIG. 3 of an HVAC system according to another embodiment of the invention; FIG.

Fig. 7 is a schematic diagram of an exemplary HVAC plant having multiple load circuits and demand control as appropriate to the practice of the invention; and

Fig. 8 shows the interaction of demand control and consumer circuit in one

Plant according to Fig. 7 according to an embodiment of the invention.

WAYS FOR CARRYING OUT THE INVENTION

The present invention is based on considerations that relate to a model heat exchanger, as shown in Fig. 5. The heat exchanger 23 of FIG.

5 transmits a heat flow Q from a hydraulic side with a hydraulic channel 24 to a discharge side 25, which is provided with ribs, for example, for enlarging the delivery surface, and which is flown by a medium, in particular air.

Water enters at a water inlet temperature T _n in the hydraulic channel 24 from the left and exits with a water outlet temperature T _s right from the hydraulic channel 24 again. The water passes through the heat exchanger 23 with a mass flow rh and a volume flow V. For the transition of the heat flow Q is the hydraulic channel 24, an area A _{j) men} available. On the discharge side 25, the secondary medium (air) flows with an input side air inlet _temperature T ^ _jn and a _Output side air _{outlet temperature} T _a ^L _us on an area A _amsen with a mass flow m _outside and a volume flow V _outside over.

For the heat flow Q flowing from the hydraulic channel 24 to the discharge side 25, the following equations result (for a stationary state):

with the heat capacity c _p on the hydraulic side (water).

^. _c . ( ^L - ^L

outside p, outside one out.

with the heat capacity c _sen on the discharge side (air).

(3) Q = ^{k A>} " ^■ (AT)" (K = unit Kelvin)

K with a heat transfer coefficient k according to the following known equation

(4) k =

_ | _ s ■ A -, ' ⁿⁱ ? , ⁿ _ (_ A inside

inside outside material an AT according to the following known equation (logarithmic mean) - jp. ^e '" ^{aUS em OUS} (F = correction factor

V. from a J

to take account of the type of heat exchanger, i. Direct current, cross current, etc.), and a power n to be determined.

From these equations results for the case n = 1 for the heat flow Q.

(6) Q = on

1 1

+ - -. + - k-A-F 2-V-rp-c p 2-V outside r p outside c p, outside

and the maximum value Q asymptotically reached for large volume flows V "

(7) outside _™ 0 = a 2 a KAF-V _a a _u u _s s _s s _e e _n n pr _a au "SSE" n "cp"

For the simplified case where n = 1, the ratio QIQ ^, i. for the

Fraction of saturation reached or degree of saturation of the heat exchanger, the following simple relationship: w _ _w

lO * Z - 1 on __ f (T ^W

O '.A ¹ ~ ^' r LV _ r LJA ¹ a ' ¹ off' ^{1 on} ''

an em

For a generalized case with general n and linearized equation (3): (9) Q = 1 - ms_ ₌ f (T ^w T ^w T ^L

L J 2 \ an 'out' ei) ·

ß • max 2 · (Θ + «· (1 - Θ)) ^' Γ _Ε with the dimensionless average temperature difference Θ to describe the Taylor series used in the linearization, which provides good accuracy with the constant value Θ = 0.7.

The two equations (8) and (9) can be given by a single equation of the form

B is dependent on the type (but not on the size) of the heat exchanger. For a pure countercurrent heat exchanger B = 1/2 (see equation (8)), for another heat exchanger B can be determined with

2 · (Θ + n ^■ (1 - Θ)

Essential in this result is that the degree of saturation of the heat exchanger under certain circumstances is a function of three relatively easy to measure temperatures, in the present case Τ ^, Τ ^, Τ ^. Should therefore be limited in an HVAC system, the scheme to the extent that when reaching a given degree of saturation Q / Q _mm (of eg 0.8) in the heat exchanger, the flow on the

Primary side of the heat exchanger is limited, it may - if the functional dependence ^¬ From the degree of saturation is known from the temperatures - due to a ^¬ times the measurement of three temperatures (on the primary-side inlet and outlet and at the se- the customer side entrance) of the heat exchanger happen. If the degree of saturation is known, the corresponding volume flow can then also be determined from a (known) curve according to FIG. 2. It can thus be dispensed with the relatively complex use and installation of a flow meter on the primary side of the heat exchanger. However, such a flowmeter can optionally be used for calibration.

In Fig. 3 an embodiment of a HVAC plant according to the invention is shown in a comparable to FIG. 1 illustration. The HVAC system 1 0 of Fig. 3 differs from the HVAC system 1 0 'of Fig. 1 first in 2 essentially things: First, the use of a flow meter 1 8 is not mandatory, but only optional, if necessary one Calibration to perform. On the other hand, a third temperature sensor 22 is arranged on the secondary-side input of the heat exchanger 1 5, which is connected to a further input of the controller 21. The third temperature sensor 22, in contrast to the room temperature sensor 27 in FIG. 1, does not measure a room temperature but the air inlet temperature T _{n of} the air flowing into the heat exchanger 15 (air stream 16). At this point it should be noted that instead of the control valve 1 7 of course, a controllable pump or - if the heat transfer medium is gaseous - a fan (or an air damper) can be used to influence the flow on the primary side.

The controller 21 measures by means of the three temperature sensors 1 9, 20 and 22, the 3 Tempe ^¬ temperatures T _n , and T ^ _m and determines therefrom by means of a known functional

Dependence of heat

exchanger. Exceeds the saturation level a predetermined limit value, which may be at ^¬ play, at 0.8, the primary-side volume flow V of the heat exchangers is shear, even if a larger volume flow is requested by the control due to a changing room temperature.

In the simplest case, the determination of the degree of saturation takes place in accordance with equation (8) given above. In other cases the equation (9) given above may be more suitable. Other functional dependencies are also conceivable within the scope of the invention.

In addition, if the optional flow meter 1 8 installed, the heat flow can be determined in a conventional manner and thus an assumed functional dependency

be checked or calibrated. In particular

It is also conceivable that such a flow meter 1 8 used only when commissioning a system and then omitted during subsequent operation.

In another embodiment of the inventive method is determined by the method described that the heat exchanger has exceeded a predetermined degree of saturation or is in saturation, so no longer can transfer heat. In this case, the system is informed that the flow temperature should be increased. This can happen by the temperature of the central flow in the flow line 1 1 is increased. In circuits with a constant volume flow, a special valve sits in each case where it can regulate the flow temperature of the consumer. A special case arises when an air stream 1 6 is to be cooled with a system according to FIG. 3, which contains moisture which condenses on cooling in the heat exchanger 1 5 and discharged as condensate from the heat exchanger 1 5 can. This is especially the case in tropical areas with high humidity and can be used specifically for dehumidifying the room air.

In this case of operation, part of the heat transferred to the air in the heat exchanger, AQ, is not consumed to cool the air but to condense the moisture. The total refrigerant flow is thus greater and the limit value for the associated primary-side volumetric flow is thus reached earlier than the value determined from the three temperatures of the refrigeration flow for the cooling of the air {Q in FIG. 4). If this is taken into account, a correction can be made which takes into account the moisture content of the air flowing through the heat exchanger 15. For this purpose, according to FIG. 3, a moisture sensor 26 can be arranged in the air stream 1 6, which measures the moisture content of the air and transmits the measured values to the controller 21. From the measured temperature values and the measured moisture content, the controller 21 then determines the refrigerant flow AQ which is needed exclusively for the condensation and which has to be added to the value required for the cooling of the air (Q in FIG. 4) by the correct associated one Volumetric flow according to the curve of Fig. 4 to determine. A limit value for the volume flow is thus reached earlier in the case of condensation than without condensation.

Another possibility of operation is in an HVAC system 30 according to FIG. 6 on the secondary side of the heat exchanger 1 5 by means of the temperature sensors 22 and

27 to measure the inlet temperature T ^ _n and outlet temperature T ^ _{s of} the air in the air stream 1 6 and (in an analogous manner as described above) from these measurements in connection with a primary-side temperature measurement on the saturation level of the heat exchanger 1 dependent on the secondary-side volume flow 5 and so to close on the secondary side flow rate (the heat exchanger 1 5 is considered to some extent in the reverse direction).

This variable can then be used to intervene in the secondary-side volume flow of the heat exchanger 1 5 regulating or limiting. This can be done by means of a controller 21 controlled by the blower 29, which is arranged in an air channel 28 which leads to the heat exchanger 1 5 out (or away from the heat exchanger 1 5). Instead of the blower can be provided as a control means but also a controllable air damper, or - if the secondary medium, for example, is liquid - a pump or a control valve.

Such a control is particularly advantageous if - as is often the case - in a HVAC system already a temperature sensor 27 is installed on the secondary side output of the heat exchanger 1 5.

In principle, however, it is also conceivable within the scope of the invention ^to measure only the temperatures T "and TL _S and to use them for control in heat exchanger operation.

The present invention can be advantageously used in HVAC systems with a so-called demand control, which are becoming increasingly important in terms of increased energy efficiency.

7 shows a schematic representation of the exemplary design of a HVAC system 40 with demand control. The HVAC system 40 includes in the example five consumer ^¬ cherkreise 34a-e, from a central power generator 31 via a distributor 32 and the corresponding supply lines 47a, b with heat and / or Kälteener- be supplied. In the individual consumer circuits 34a-e, a heat exchanger 35 is in each case arranged, which transfers the supplied energy to a consumer 36.

The provision of the energy by the energy generator 31 and the distribution of the energy through the distributor 32 is controlled by a demand control 33 via corresponding control lines 41 and 42. In addition, the demand control 33 can intervene in the individual consumer circuits 34a-e on the consumer side via corresponding control lines 39, in order, for example, to change the secondary-side volume flow in the relevant heat exchanger 35.

Demand control 33 receives demand signals from consumer circuits 34a-e via demand signal lines 38, which are then evaluated to control power generation and distribution so as to cover the demanded demand in a manner that meets predetermined criteria, e.g. energy efficiency is optimized.

For this optimization, information about the respective operating state of the heat exchanger 35 is required, namely the inlet and outlet temperatures, the degree of saturation, the primary and secondary flow rates and - if air is used as the medium - the moisture content of the air.

According to the invention, this information can be attributed to simple temperature measurements and, if necessary, humidity measurements, without having to use elaborate flowmeters. Accordingly, temperature values are transmitted from the heat exchanger 35 via temperature signal lines 37 to the demand control 33 (a signal line for the moisture measurement is not shown in detail in FIG. 7).

The structure in the individual load circuit 34n is shown in FIG. With the temperature sensors 43a-d, input and output sides are connected on the primary side and the secondary side. temperature T1, T3 and 12, 14 measured, and optionally with a humidity sensor 44, the relative humidity. The consumer 36, which is arranged on the secondary side of the heat exchanger 35, flows through the secondary medium, which is moved in a circuit, for example, by means of a delivery device 45, a pump, a blower or the like. The volume flow of the secondary medium can be influenced either via the conveying device 45 or via a separate regulating means 46, a valve, a flap or the like. From the consumer 36 itself comes a demand signal and is forwarded via the demand signal line 38 to the demand control 33.

From the measured temperatures T1-T4, the degree of saturation of the heat exchanger 35 and the volume flows can be determined according to the invention. If the optimization of the demand control 33 requires a secondary-side intervention, this can be done by means of the control lines 39a, b via the conveying device 45 and / or the control means 46.

If the optimization of the demand control 33 requires an intervention in the distributor 32, this can be done via the control line 42. An intervention in the power generator 31 is performed via the control line 41. Such an intervention may be, for example, to change the flow temperature. However, it is also conceivable to change the total power generation step by step if in the power generator 3 1 several similar modules (eg refrigerators) work in parallel and can be controlled individually, as disclosed for example in the document US Pat. No. 7,377,450 B2. LIST OF REFERENCE NUMBERS

1 0, 1 0 ', 30 HVAC plant

1 1 supply line

1 2 return line

1 3 supply branch line

1 4 return branch line

1 5.23 heat exchanger

1 6 Airflow

1 7 control valve

1 8 flow meter

1 9,20 Temperature sensor

21 control

22,27 temperature sensor

24 hydraulic channel

25 delivery side

26 humidity sensor

28 air duct

29 blowers (fan)

31 energy producers (heating / cooling energy)

32 distributors

33 demand regulation

34a-e, n consumer circle

35 heat exchangers

36 consumers

37 temperature signal line 38 demand signal line

39,41, 42 control line

39a, b control line

40 HVAC system

43a-d temperature sensor

44 humidity sensor

45 conveying device (e.g., pump, blower, etc.)

46 control means (e.g., valve, flap, etc.)

47a, b supply line

RTS room temperature sensor

Q Heat flow öm _a x ^max - Heat flow (at saturation) Q Condensation cooling flow

V flow rate (water)

T _n water inlet temperature

TZ _* water outlet temperature

T ^ _n air inlet temperature

TL _* air outlet temperature

T1 -T4 temperature

Claims

claims

1 . Method for operating a heat exchanger (1 5), which heat exchanger (1 5) flows through a heat transfer medium on a primary side, which enters the heat exchanger (1 5) at a first temperature (T1, T _n ) and at a second temperature ( T2, T ^ _s ) from the heat exchanger (1 5) emerges, and on a secondary side in the heating case, a heat flow (Q) to a through the heat exchanger (1 5) flowing secondary medium or in the cooling case, a heat flow (Q) from the secondary medium receives, which at a third temperature (T3, T ^ _in ) enters the heat exchanger (1 5) and at a fourth temperature (T4, T _a ^L _lls ) exits the heat exchanger (1 5) again, wherein the heat exchanger (1 5) can transmit a maximum heat flow (), characterized in that at least three of the four temperatures (T1-T4, T _n, TZ _{s <TL} · T are measured _off), and in that from these measured temperatures of the respective saturat.flux Degree of (P) of the heat exchanger (15) and determines the

Control of the operation of the heat exchanger (1 5) is used.

2. The method according to claim 1, characterized in that the flow of the heat transfer medium on the primary side of the heat exchanger (1 5) is controllable, and that the flow of heat transfer medium on the primary side of the heat exchanger

(1 5) is limited when the degree of saturation (

) of the heat exchanger (1 5) ömax

reaches a predetermined value.

3. The method according to claim 1, characterized in that the flow of the secondary medium on the secondary side of the heat exchanger (1 5) is controllable, and that the degree of saturation (- -) of the heat exchanger (1 5) for controlling the

•Max

Current of the secondary medium is used.

Method according to one of claims 1 -3, characterized in that the heat transfer medium is water.

Method according to one of claims 1 -4, characterized in that the secondary medium is air.

Method according to one of claims 1 -5, characterized in that the heat exchanger (1 5) is part of a HVAC system (1 0).

Method according to one of claims 1 to 6, characterized in that the first, second and third or fourth temperature (T1, 12, T3 or T4; T _n , T _s , T _e ^L _in or

T,), and that for determining the degree of saturation (

ß ^■ .max of the heat exchanger (1 5) a function of the type Q

= f (T1, T2, T3,4) or

•Max

is used.

Max

8. The method according to claim 7, characterized in that the heat exchanger is operated in countercurrent, and that for determining the degree of saturation

9. The method according to claim 7, characterized in that the heat exchanger is operated in countercurrent, and that for determining the degree of saturation

(- -) of the heat exchanger (15) the function

where n is one of ö _ma * 2 · (Θ + ι · · (1-Θ)) T -T ^,

Value 1 denotes a different power and Θ is a constant which in particular has the value 0.7. 10. Method according to claim 5, characterized in that, in the case of cooling, the moisture content of the air is additionally measured on entry into the heat exchanger (15), and that the temperature (T1, T2, T3 or T4, T _n , T _s .

the heat exchanger (15) to ömax

Taking into account a taking place in the heat exchanger (15) condensation is corrected accordingly.

1. The method according to claim 1, characterized in that the flow temperature (T1, T _n ) of the heat transfer medium is increased when the degree of saturation () of the heat exchanger (15) reaches a predetermined value. 2. HVAC system (10, 30, 40) for carrying out the method according to any one of claims 1-11, comprising at least one heat exchanger (15, 35) which pri märseitig to a flow line (11) and a return line (12) a working with a heat transfer medium central heating / cooling system (31) is connected and flows through the secondary side of a secondary medium, further comprising a control means (17, 29, 45, 46) for controlling the pri märseitigen mass flow of the heat transfer medium and / or Secondary flow, and a first temperature sensor (19, 43a) for measuring the inlet temperature (T1, T _n ) of entering the heat exchanger (15, 35) heat transfer medium, a second temperature sensor (20, 43b) for measuring the outlet temperature (T2, T _s ) of the heat exchanger (15, 35) exiting

Heat transfer medium, and a controller (21, 33), to which the input side of the first and second temperature sensor (19, 20, 43 a, 43 b) are connected, and the output side to the control means (17, 29, 45, 46) is connected, characterized in that at least one third temperature sensor (22, 27, 43c, 43d) for measuring the inlet temperature (T3, T _e ^L _jn ) and / or outlet temperature (T4, T ^) of the secondary side entering the heat exchanger (15, 35)

Secondary medium is provided, that the third temperature sensor (22, 27, 43 c, 43 d) to an input of the controller (21, 33) is connected, and that the controller (21, 33) is designed so that it controls the control means (17, 29, 45, 46) in accordance with the temperature values measured by the at least three temperature sensors (19, 20, 22 or 27; 43a-d).

13. HVAC system according to claim 12, characterized in that on the heat exchanger (15, 35) on the secondary side a consumer (36) is connected, and that the controller (33) via a demand signal line (38) from the consumer (36)

Receive demand signals.

14. HVAC system according to claim 12 or 13, characterized in that the heat transfer medium is water and the secondary medium is air.

15. HVAC system according to one of claims 12-14, characterized in that the control means is a control valve (17), which in one to the primary side of

Heat exchanger (15) leading flow branch line (13) or return branch line (14) is installed.

16. HVAC system according to claim 14, characterized in that the control means is a fan (29), which is installed in a to the secondary side of the heat exchanger (15) leading air channel (28).

17. HVAC system according to claim 14, characterized in that a moisture sensor (26, 44) for measuring the moisture content of the heat exchanger (15, 35) inflowing air is provided, and that the humidity sensor (26, 44) to an input the controller (21, 33) is connected. 18. HVAC system according to one of claims 12-17, characterized in that a flow meter (18) is provided, which in one to the primary side of the Heat exchanger (1 5) leading flow branch line (1 3) or return branch line (1 4) is installed, and that the flow meter (1 8) is connected to an input of the controller (21).

HVAC system (40) according to claim 1 2, characterized in that a plurality of heat exchangers (35) are arranged in a plurality of consumer circuits (34a-e) that the consumer circuits (34a-e) of the central heating / cooling system or energy generator (31 ) are powered by a distributor (32) that the controller (33) comprises a demand control, and that the controller (33) via control lines (41, 42) to the power generator (31) and the manifold (32) is connected ,